Decurling apparatus



July 7, 1959 E. P. POWELL DECURLING APPARATUS 2 Sheets-Sheetl Filed June29, 1955 [ria L f @www NR m E. P. POWELL `luly 7, 1959 DECURLINGAPPARATUS 2 Sheets-Sueet Filed June 29, 1955 /M/s/ vraR ER/vEfr/Q POWELL0s www, Av-rangers United States Patent ARBARATUS Ernest l?. Powell,Philadelphia, Pa.,A assignor to E. G. Stande Manufacturing Company,Inc., St. Paul, Minn., a `corporation of New Hampshire `AmxlicationJune- 29,` 119.55., vSfal'ial N o. 518,7 6.1

3 Claims. (Cl. 18-1) This invention relates to a mechanism for decurlingand leveling strip .material such as; plastic tilms, paper, cardboard,etc. More. ParticularlyV this invention relates to apparatus fordecurling and leveling thermoplastic strip material prior tofeeding-itto a box making-machine.

The principal object: of this invention is to provide apparatus forhandling strip material fromV a supply roll for feeding the strip forfurther treatment in flat conditionl free from curls and surfaceirregularities.v

Other objects ofthe invention will become apparent as the descriptionproceeds.

To the accomplishment, of the foregoing and related ends, this inventionthencomprises the features hereinafter fully described and particularlypointed out in the claims, the fol-lowing description setting forth indetail certain illustrative embodimentsv of the invention, these beingindicative, however, of but a f ew of the various ways; in which theprinciples of the invention may be employed.

The invention is illustrated by the drawings in which the same numeralsrefer to corresponding parts and in which:

Figure l is a side elevation of the decurler mechanism of thisinvention;

Figure 2 is a fragmentary end elevation of the apparatus taken on the,line. of Figure 1 and in the direction of the arrows;

Figure 3 is a transverseyplan view, of the lower part of the apparatus,partly in section, taken on the line 3-3 of Figure l and in the.direction of the arrows, showing the oating roll and associated parts;and

Figure 4 is an enlarged detail elevation, in section, of the meteringvalve.

Referring to the drawings, the apparatus for decurling strip materialcomprises a base (not shown) from the front end of which rises a pair ofperpendicular laterally spaced posts or columns 10, preferably tubularin form. Connected to andl supported by, columns are a pair of parallelhorizontal supports 11 on which a shaft 12 for carrying a supply roll 13of strip material is suitably mounted for rotaryA movement.

When the subsequent treating,v steps are those involved in making boxesfrom plastic, the strip material (from which the curl is to be removedto be delivered flat for further treatment) is a thermoplastic resinoussubstance such asv cellulose acetate, plasticized vinyl chloridepolymers, vinyl chloride-vinyl acetate copolymers and the like which arereadily deformed by the application of heat and preferably areself-welding.

Although this apparatus is especially adapted for removing curls fromthermoplastic sheet material, it is to be understood that it is likewiseadapted for treating other strip materials, such as paper and cardboard,particularly resin coated or treated paper and cardboard, before theyare subjected to further treatment, such as printing, blanking formaking boxes andlike operations, to remove any curls and surfaceirregularities and undulations. Although the apparatus is described withparticular reference to decurling of thermoplastic sheet material, itwill be understood not to be so limited.

A drive roll 14. carried on a shaft l5 is mounted on and supported bycolumns itl at their upper ends. One end of shaft i5 is provided with apinion (not shown) driven by a standard pneumatic motor ld. Motor 16 ismounted on a frame member l? supported by bracket i8 at the top of oneof coiumns it?. The opposite end of shaft 15 is journalled in acorresponding frame member 17 supported by a similar bracket t8 at thetop of the other column.

The strip 19 of thermoplastic sheet material is drawn from supply roll lover drive roll .te and thence downwardly over a pivotally mountedheated roll Ztl, over a xed guide and cooling roll 2i., around, alloating tension roll 22 and upwardly around a guide roll 24 to be fedto the treating apparatus. Arranged between the guide roll 2l and thefloating roll 22 is a pair of laterally spaced guide iingers carried bycolumns lil. These guide fingers engage the opposite edge portions ofthe strip 19 as the latter advances and may be curved to trough or causethe edge portions of the strip to be given a reverse curl, lengthwise ofthe sheet, for the purpose of assisting in straightening out thecontinuous sheet to obtain a strip which is as flat and free fromundulations as possible.

Drive roll T14 is preferably provided with a cloth cover, such as felt,to improve traction with the strip i9 while at the same time providing arelatively soft surface over which the strip may pass freely withoutbecomf ing scratched. Guide roll 2l acts to cool the strip as it passesfrom the heated roll. if necessary artificial cooling may be used, suchas circulating brine, but in most instances it is suficient merely toallow free circulation of air by providing openings in the ends of theroll.

Heated roll 2t) is mounted on and rotates about a shaft 26 xedly carriedat its opposite ends by arms 27 which in turn are keyed to shaft 28which is journalled for rotation in brackets 29 which are mounted on andsupported by frame members i7. At one end of shaft 2S which extendsbeyond one of brackets V29 there is keyed a crank arm Sil extendinggenerally upward as an extention of arms 27. rthe upper end of crank armSi) is pivotally connected to the piston rod 3l of an air cylinder 32pivotally mounted on one of frame members i7.

A coil spring 3d, one end of which is mounted on crank arm 39 and theother end of which is fixed to one of frame members i7 adjacent the axisof drive roll 14, tensions crank arm 3d toward roll lili and accordinglyurges heated roll 2t? and its accessory mounting away from the driveroll and the path of travel of the strip 19, as shown in broken lines inFigure l. As will be explained hereafter, this prevents reverse curlingdue to overheating of the strip. Heated roll Ztl is provided with aplurality of resistance heating elements connected to a suitable sourceof electrical energy by means of conductors passing through xed shaft2.6 and suitably insulated from the roll and shaft.

The air inlet end of cylinder 32 is connected by means of tube S5 to asolenoid operated valve 36. Valve 3 6 is provided with an air inlet 37and an air outlet 38. When the solenoid is not enero-ized, the plunger40 of the valve is urged forward by coil spring di. Piston 4Z is pushedfree of the air inlet 37 but piston 44 shuts off the air outlet 38. inthis position air from any suitable source of compressed air is free topass through inlet 37, through the valve and tube 35 to cylinder 32where it pushesfpiston rod 3l. and crank arm 5t) forward, acting againstspring 34 and pivoting arms 27 and heated roll V20 backward toward driveroll id, as shown in solid lines in Figure l.

Solenoid 39 is connected by means of conductors 45 and 46 to a source ofelectrical energy 47 through a switch 48 actuated by oating roll 22 aswill be explained in detail hereafter.

The oating tension roll 22 is carried in a yoke 49 which in turn iscarried by a rigid arm 50 keyed to a rotatable shaft 51 journalled inbrackets 52 and 53 mounted on column 10. A counterweight 54 for thefloating tension roll 22 is carried on an arm 55 keyed to shaft 51.

A crank arm 56 is keyed to shaft 51 at one end thereof extendingsubstantially parallel to yoke arm Sil. Upper and lower stops 57 and 58are provided on bracket 53 for limiting the movement of crank arm 56and, accordingly, of the tension roll 22. Crank arm 56 has a projectinglug 59 which displaces spring arm 65 when the tension roll is lowered,thereby actuating switch 48 and energizing the solenoid 39, bleeding airfrom cylinder 32 and permitting spring 34 to retract heated roll 20 awayfrom the path of moving strip 19.

Pivotally connected to the end of crank arm 56 is a link 61 in turnpivotally connected at its opposite end to an operating arm 62 which ispart of a metering valve 64 which will now be described in detail withparticular reference to Figure 4.

Metering valve 64 controls the supply of air to pneumatic engine 16.This air engine is of -a type well known in the art and since theparticular construction forms no part of this invention, it will not bedescribed further except to state that it is provided with air underpressure from any suitable source through a tube 65 to air inlet 66 ofthe metering valve, through the valve to outlet 67 and thence throughtube 68 to motor air inlet 69 and nally the air is discharged throughoutlet 70 to tube 71.

Metering valve 64 comprises a housing having a generally cylindricalpassage 72 extending vertically therethrough. At its upper end there isa valve seat member 74 having a valve seat 75 and its lower end isnarrowed to receive a guide member 76 with a sliding seal fit.Positioned within passage 72 is a rack 77 carrying a tapered valvingmember 7S at one end and guide 76 at the other. Meshing with the teethof rack 77 is a pinion 79 rotatably mounted in a cavity in the valvehousing keyed to a shaft 80 journalled therein, one end of which extendsthrough the valve housing. Operating arm 62 is keyed to shaft S0,outside of the valve housing. Rack 77 is held against pinion 79 by ascrew 81, but without restricting movement of the rack.

When floating tension roll 22 is lowered because it is released from thestrip 19, due for example, to breakage of the strip or reaching the endof the supply roll, or any other reason, the switch 48 acts to energizethe solenoid and disengage heated roll 20 in the manner heretoforedescribed. At the same time, crank arm 56 moving downwardly with thetension roll assembly exerts a pull on link 61 which in turn lowersoperating arm 62. Because operating arm 62 is keyed to the sarne shaftas pinion 79, the pinion is rotated and rack 77 is raised, pushingtapered valving member 78 against the valve seat and shutting off thesupply of air to the air motor.

Because the decurler apparatus of this invention is especially adaptedfor use with a box making machine of the type described in a copendingUnited States application Serial No. 265,734, led January 10, 1952, byLuther Earl Sevison and other similar treating apparatus which impartsan intermittent step-by-step movement to the strip 19, it is necessarythat air motor 16 operate at different rates of speed. It will beapparent from the description of the operation of the metering valvethat the operation of the air motor is controlled by the movement of thefloating tension roll 22.

When a pull is exerted on the strip 19 by the mechanism in advance ofthe guide roll 24, the tension roll 22 is caused to swing upwardly. Thismovement raises crank arm 56, link 61, arm 62 and lowers rack 77withdrawing tapered valving member 78 somewhat from the valve seat andpermitting greater ow of air to the air motor. A slowdown in thetreating mechanism in advance of the decurler causes tension roll 22 tolower somewhat and in turn decreases the supply of air to the motor.

Instead of the air motor illustrated and described, it will be apparentthat a variable speed electric motor or similar variable speed drivecould be used. Metering valve 64 would then be adapted to control the owof electrical energy instead of air. For this purpose, a rheostatoperated by arm 62 in response to movement of the tension roll wouldbesubstituted as the metering valve.

In the operation of the decfurling device of this invention, the strip19 is threaded from supply roll 13 over drive roll 14, in a reverse bendaround heated roll 20, reversed again around cooling guide roll 21,around tension roll 22, up and `around guide roll 24 and thence to thefeeding mechanism of the boxrnaking or other treating apparatus, Thestrip is pulled by the feeding device of the subsequent treating machineas well as being driven by drive roll 14.

The thermoplastic sheet is rendered somewhat pliable as it passes incontact with heated roll 20 while in a reverse bend from its position onthe supply roll. While thus pliable, the strip as it leaves the heatedroll is directly given another reverse bend and cooled as it passes overguide roll 20. This combination of treatment acts to restore the stripto its original substantially at condition free of curls. A tendency ofsome materials to curl at their edges may be overcome by passing thestrip between guides 25 ourved and placed together closer than the widthof the strip, to trough it slightly, thereby eliminating curlingdifficulties lengthwise of the sheet.

During normal operation the solenoid 39 is de-energized and the pistonsof valve 36 are positioned to permit free passage of air from a sourceof air under pressure to inlet 37, through valve 36 and tube 35 tocylinder 32. The piston of the air cylinder pushing against crank arm 30pushes and maintains the heater roll 20 and its accessory assemblypivoted on shaft 28 against the moving strip 19.

The oating tension roll 22 and its accessory assembly are maintainedsubstantially level during normal operation by moving strip 19 andcounterweight 54. In this position switch 48 is kept open and meteringvalve 64 is set so as to provide the requisite amount of air to the airmotor 16 to drive it at the desired speed.

In the event of a speed-up in the treating mechanism in advance of thedecurler the resulting pull on strip 19 raises tension roll 22 and, asheretofore explained, feeds more air to the air motor increasing therate of speed of the drive roll 14. In the event of a slowdown tensionroll 22 drops somewhat and causes the metering valve to reduce the ow ofair to the air motor diminishing its speed.

If the slowdown is of a more serious nature, such as a stoppage inmovement of the strip or a break in the strip or the end of a supplyroll, then the tension roll drops down against lower stop 58 and in sodoing causes lug 59 on crank arm 56 to depress spring arm 60 closingrswitch 4S and energizing solenoid 39. As described above, this causesthe plunger of valve 36 to move shutting off the air supply to cylinder32 and bleeding air out of the cylinder. This causes the heated roll toretract, avoiding damage to the strip due to over heating, or the stripis broken or the supply roll is exhausted, it facilitates rethreading ofthe strip. At the same time, the tension roll in this lower positionshuts off the supply of air to the air motor stopping the drive roll.

It is apparent that many modifications and variations of this inventionas hereinbefore set forth may be made without departing from the spiritand scope thereof. The specic embodiments described are given by way ofexample only and the invention is limited only by the terms of theappended claims.

I claim:

1. A decurling device for continuously treating the surface area of acontinuous length of thermoplastic sheet material comprising meansadapted to hold a source of supply of sheet material, a pivotallymounted rotary heater, a drive roll for advancing said sheet materialpast the rotary heater, a variable speed motor for driving said driveroll, guide means for changing the direction of movement of said sheetmaterial in advance of the rotary heater, a counterweighted pivotallymounted tension roller responsive to changes in tension of said sheetmaterial in advance of said guide means, control means for varying thesupply of energy to said motor to vary the speed thereof, said controlmeans being operatively connected to and responsive to changes inposition of said tension roll, an air cylinder operatively connected tosaid pivotally mounted rotary heater to move the same toward and awayfrom the path of travel of the sheet material, said rotary heater beingmoved out of contact with the sheet material in the event of breakingthe continuity of the sheet, a solenoid actuated valve for controllingthe supply of air to said cylinder and a switch for controlling ow ofelectricity for energizing said solenoid, said switch means beingresponsive to movement of said tension roller.

2. A decurling device according to claim 1 further characterized in thatsaid valve for controlling the supply of air to said motor comprises agenerally cylindrical passage, an air inlet at one end of said passageand an air outlet at the other end thereof, a valve seat adjacent theoutlet end of the passage, a rack within the passage, a taperedelongated valving member carried at one end of said rack adapted to seatin said valve seat, a pinion engaging the teeth of said rack, saidpinion being operatively connected to and rotatable in response tochanges in position of said tension roller.

3. A decurling device for continuously treating the surface area of thelength of sheet material without applying lateral tensile stress theretocomprising means adapted to hold a source of supply of sheet material, aheating element, drive means for advancing said sheet material past theheating element, said drive means including a drive roll, a pneumaticmotor for driving the roll, and valve means for controlling the airsupply to said motor, guide means ahead of the heating element forchanging the direction of movement of sheet material, a pivotallymounted tension roller ahead of said guide means, control meansresponsive to the movement of said tension roller for varying the speedof said drive means and for retracting the heating element from the pathof travel of the sheet material in the event of breaking the continuityof the sheet, said valve means being responsive to changes in positionof said tension roller, and said valve means including a generallycylindrical passage, and air inlet at one end of said passage and an airoutlet at the other end thereof, a valve seat adjacent the outlet end ofthe passage, a rack within the passage, a tapered elongated valvingmember carried at one end of said drive in cooperation with said valveseat, a pinion engaging the teeth of said latch, said pinion beingoperatively connected to and rotatable in response to changes inposition of said tension roller.

References Cited in the tile of this patent UNITED STATES PATENTS2,547,836 Pfeier Apr. 3, 1951 2,597,877 LeClair May 27, 1952 2,702,406Reed Feb. 22, 1955v 2,737,089 Baumgartner Mar. 6, 1956 2,745,134 CollinsMay 15, 1956 FOREIGN PATENTS 1,015,939 France Oct. 28, 1952 1,070,273France July 21, 1954

